This invention relates to a gas burner and particularly to burners for liquid gas (liquefied gas), the novel feature of which resides in the fact that the burner is provided with groups of orifices for the exit of the mixture of combustible fuel and air as the primary combustion supporter. The orifices are close together and they have minimum dimensions so that unification of the flame front is achieved. This permits one to avoid vibrations of the flame front and to eliminate a very troublesome factor of acoustic disturbance and at the same time gives rise to flames of greater uniformity and permits to achieve a greater specific combustion yield.
According to a further feature of the invention, it is provided that, when combustible fuel is used which has a low rate of flame propagation, in particular when a flame with a strong flame power is required, a fact which causes a high exit velocity of the mixture of combustible fuel and primary air as combustion supporter, pilot flames are present. The pilot flames issue from an interspace between a perforated outer plate in correspondence to the passage of the flames and the plate of the body of the burner, which is equipped with outflow orifices, the latter being very close together and of minimum dimensions for the passage of the fuel mixture.
The above-mentioned interspace is fed with the mixture of combustible fuel and primary air as combustion supporter, which mixture comes at a low outflow velocity from orifices of reduced cross section, so that a great flame stability is achieved.
As it is known, gas burners of high specific capacity generally are provided with many orifices for the outflow of the gas, each one of the orifices causing an autonomous flame front which is independent of the others. Very often the overflow orifices are joined in groups for the purposes of achieving a satisfactory feeding of the flame with a source of secondary air. However, because of the technological difficulties, the distance between the orifices up to the present has never been reduced to less than 2 mm, so that phenomena of vibration of the flame front occur which produce very troublesome noises, the noises frequently reaching intensities so high that considerable damage is caused in the enclosures where the noises are generated and where they propagate.